Following a bioterrorist attack, hundreds of thousands of potential victims may require testing and treatment. The critical need to test large numbers of people for exposure to a biothreat agent may overwhelm the capacity of the clinical and public health infrastructure. The approximately 25,000 sentinel laboratories in the Laboratory Response Network, which coordinates preparedness and response, need diagnostic tools to enable accurate decentralized testing. The goal of the proposed project is to develop a surge-testing platform for this network. The 2001 anthrax attacks showed that administering aggressive therapy to victims who have early diagnostic evidence of blood infections saves lives. Specifically, we will address the need for identifying patients that require aggressive life-saving therapy by developing a blood test for B. anthracis infection that tests for multiple-toxin and cellular antigens using the MultiPath(tm) testing system which we demonstrated in Phase I. The MultiPath system is an ideal surge-testing platform, being ultra-sensitive, quantitative, accurate, cost-effective, user-friendly, portable, and automated. The test rapidly detects multiple targets with sensitivities approaching nucleic acid amplification tests but with the cost-effectiveness and user-friendliness of over-the-counter immunoassay "strip" tests. In Phase I we showed that the MultiPath test detects protein, bacterial, and viral targets at levels up to thousands of times lower than commercial strip tests. This sensitivity comes from using a proprietary imaging approach which detects individual microparticles rather than the millions of particles required to detect a signal in standard strip tests. The system will comprise kits that acquire and automatically test blood samples rapidly (target assay time = 5 min) for sub-picogram levels of multiple B. anthracis antigens (to minimize false positives); an identification system to link patients to the test results; and a portable standalone near-patient test analyzer that will automatically process batch-loaded samples (<10 seconds per sample) and that will print and wirelessly post the results. The Specific Aims of the application are to (1) develop a prototype consumable kit containing an integrated consumable for collecting the sample and automatically running the assay; (2) develop the cost-effective batch-loadable near-patient analyzer; (3) integrate the system components; and (4) demonstrate the efficacy of the system to detect B. anthracis sensitively and specifically in whole blood samples. The Phase 2 project results and deliverables will support the Phase 3 commercialization goals for implementing the MultiPath B. anthracis test in the public health preparedness system. Follow-on products will include clinical tests for other potential biothreat and infectious agents and an instrument-free platform for detection of biothreat agents outside of the clinic. Competitive advantages of the MultiPath test include the intellectual property covering key features of the test, an unprecedented feature list of high-end results and customer-friendly attributes, and straightforward commercialization path. Besides addressing the large and growing bioterrorism market, the MultiPath test addresses significant unmet testing needs in healthcare (infectious disease, cancer, cardiovascular disease) and in industrial microbiology (food, beverage, pharmaceutical manufacturing). The value that the MultiPath test will bring to both the primary and secondary markets should attract large corporations as partners to support commercial development, marketing, and distribution.